Re: GEVs

Allan Goodall wrote:
> 
> On Fri, 3 Dec 1999 10:07:01 -0500 (EST), Roger Books
<books@mail.state.fl.us>
> wrote:
> 
> >So why use little tiny blades.  Maybe auxilliary jets?  Compressed
gas?
> >Null-G packs.
> 
> In order to lift the GEV? Well, then by definition it isn't a Ground
Effect
> Vehicle. You do make a point with the null-g packs (auxilliary jets
and
> compressed gas I think would be one use only due to "fuel" use and
would still
> be unpractical).

This was all about hopping, not about continued use.  You get a run on
normal ground affect, when you get to ditches/small hills you use your
jets/compressed gas/short duration null-g pack and hop.  Sure, they
only last 6 seconds and have to be charged again for a minute, but it
gives you more options.

> 
> But null-g packs are fantasy.

So do you run grav-tanks?

> >One other thing I still am not sure I believe is part of the vector
> >of the GEV pushing it down hill.  If the skirts follow the terrain
> >and the GEV stays level it appears to me as if the GEV would
experience
> >the same (or maybe even less) downhill force than the equivalent
> >ground vehicle.
> 
> The GEV is level. The force would be straight down. If the skirt
follows the
> contour of a slope, part of the force would be down into the back of
the
> skirt, pushing the skirt down the slope.

The part of the force pushing backwards on the skirt is exactly balanced
by
the force on the frame of the vehicle.	There is NO net thrust from the
air cushion EXCEPT for that of the escaping gas.

 Thus part of the vector is still down
> the hill. You'd also have uneven pressure in the skirt from the front
to the
> back, which I think would tend to push the front of the GEV upwards
parallel
> to the slope.

That's the wonderful thing about compressed air, it balances to the same
pressure
at all points.

You are making the mistake of thinking of this as a fan blowing air
down.  It
is not, it is compressed air in a plenum.  It doesn't press harder at
any point,
it has a standard 1 or 3 or 5 or whater psi.  All the fans do is put
more air
in to replace that escaping under the bottom of the plenum.  The only
way you
get an affect of lifting one part more than another is if the design is
poor
and one part weighs less than another, and in this case it will do this
on
level ground.

> >However, I am encountering another problem that could be
insurmountable.
> >GEV over water, when the pressure required to hover (say 10psi)
exceeds
> >the mass of the water underneath (not very well put, but I hope it
gets
> >the idea across) wouldn't the vehicle sink?	Anyone know at what
pressure
> >this would occur.
> 
> Yep, the vehicle would sink. I'm not sure what pressure you'd need,
but the
> GEV would sink if the pressure exceeds the mass of the water. Floating
on a
> cushion of air over water is similar in effect to floating a boat.

I can see it now, you drive your tank across the swamp, going fine over
the
muck as the water is pushed away, when you hit the main channel where
the
water is 20 feet deep.	At least you make lots of bubbles as you go
down. :)

Roger